Blue Smoke when idling - WHY?

[Captain Mal]

Recently noticed some exhaust smoke at idle. Changed oil brands and drove from Florida to Pennsylvania to pick up a trailer. LOTS of dark-blue smoke while idling. No oil consumption noticed, but I dumped the new oil and went back to Rotella. Still lots of blue smoke at idle. The engine runs cleanly, even under heavy loads, but smokes at idle.

Grossed 18K lbs. with my tow to Palm Beach, FL today. No oil consumption but the smoking continues. Pouring lots of magic ju ju into the fuel to try and clean the injectors. Have noticed a little improvement but it still smokes a lot at idle only. Truck runs strong with good fuel mileage.

Could it be an injector problem? My dealer is in Pennsylvania but I live at my winter house in Florida right now. The truck has over 120K miles on it and is out of warranty. What do I fix?

'01 GMC D/A ext. 2500 sb 4x4

[technician]

Captain Mal,

Are you overtreating with "majic Ju-Ju" ?
How long did you run the other oil ?
Do you idle much?

I once switched from Rotella to another brand & experienced smoking & oil consumption. Switched back and all was well again. Can't remember how long the switch back took to cure the oilusage problem... Also Rotella has a high detergent it may be cleaning out the other oil.
Good luck!

[Captain Mal]

Technician,

Somehow I ended up with two different posts on the same topic. If it could happen it does to me.

In answer to your comments I MAY be overtreating with the 3 different types of fuel treatment I bought. I'll have to follow suggested amounts.

I only had the 'new' oil in for 1,400 miles which was 2 days. Never had any oil consumption. No oil consumption on Rotella for the last 3 days and 1,600 miles of mostly towing.

Doing a 3,500 mile tow starting Monday. If it's still smoking when/if I return I will do what John Kennedy suggested and look at injector balance.

Thanks,

'01 GMC D/A sb 4x4 ext.

[LanceW]

I almost hate to ask, but are there any permanent effects from over-dosing on the additives? I accidentally doubled the double-dose (!) on my last tank.